Aliens speaking? Mysterious signals from sun-like star intrigue astronomers
The star has been identified as HD164595, located in the constellation Hercules. It is a star of 0.99 solar masses and estimated to have an age of 6.3 billion years.
There is at least one planet in its system, called HD 164595 b and is about the same size as Neptune. In fact, it is referred to as a “warm Neptune,” orbiting its star every 40 days.
The signal that the astronomical world is so concerned with now was first detected in May 2015 by Russians with aid of the the RATAN-600 radio telescope at a facility in the republic of Karachay-Cherkessia, not far from the Georgian border.
It had a wavelength of 2.7 cm (1.06 inches) and amplitude of 750 millijansky, or mJy, a unit of measure specifically used in radio astronomy.
Researchers are puzzled no less than they are excited. It can’t be ruled out that the signal was coming from a radio beacon built by extraterrestrial civilization. To theorize on the possible contact, they use the so-called Kardashev scale, one of the ways to measure an alien society's technological advancement based upon how much energy it has at its disposal.
“Working out the strength of the signal, the researchers say that if it came from an isotropic beacon, it would be of a power possible only for a Kardashev Type II civilization. If it were a narrow beam signal focused on our Solar System, it would be of a power available to a Kardashev Type I civilization,” Paul Gilster wrote at Centauri Dreams.
However, this cannot, so far, be scientifically proven. There have been no subsequent signals tracked to HD 164595 detected in the more than 15 months since it was recorded.
“We can’t claim the detection of an extraterrestrial civilization from this observation,” Gilster said. “What we can say is that the signal is interesting and merits further scrutiny.”
This is where Search for Extraterrestrial Intelligence, or SETI, gets involved. Two research groups are going to track HD 164595 Monday. The SETI Institute is using the Allen Telescope Array in Northern California, while METI International is looking to the Boquete Optical SETI Observatory in Panama, GeekWire reported.
“We need to be alert to the possibility than if we do really find a signal from an advanced civilization, they are also transmitting at other frequencies than the one where we first detected them,” Doug Vakoch, president of San Francisco-based METI International, said, according to GeekWire. “That’s why it’s so important to prepare for follow-up SETI observations at both radio and optical frequencies, to be launched as soon as we detect a credible candidate signal at any frequency.”
However, some researches remain very skeptical of the possibility of finding aliens, even if the signal was real.
“The signal may be real, but I suspect it’s not ET,” Seth Shostak, senior astronomer at the SETI Institute told GeekWire. “I just did a quick calculation of how much wattage they’d need to wield from 94 light-years (I think that’s the distance) in order to produce the apparently received signal, and that would be a big utility bill, even if they were directing the transmission (as opposed to broadcasting equally in all directions).”
It is very much likely that the signal was just a case of earthly radio interference or a microlensing event. It has happened before, radio telescopes picking up random signals.
Another SETI project scientist stated that he was “unimpressed” and that “millions” of potential signals with similar characteristics had been detected.
“Because the receivers used were making broad band measurements, there's really nothing about this ‘signal’ that would distinguish it from a natural radio transient (stellar flare, active galactic nucleus, microlensing of a background source, etc.) There's also nothing that could distinguish it from a satellite passing through the telescope field of view. All in all, it's relatively uninteresting from a SETI standpoint,” Eric Korpela from University of California, Berkeley’s Space Sciences Laboratory wrote.
Nevertheless, the signal will certainly brought up at a SETI committee meeting during the 67th International Astronautical Congress in Mexico on September 27.